What absorbs at 1336 cm⁻¹ in an FTIR spectrum?
A band near 1336 cm⁻¹ can point to several functional groups. Below are the most likely assignments, ranked by how much published evidence supports each — every one traceable to literature (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.
Backed by 8 cited sources
Quick answer
A band near 1336 cm⁻¹ is usually interpreted by checking which functional groups repeatedly co-occur there in the literature, then confirming at least one or two additional peaks in the same sample. This page ranks those assignments by accumulated evidence rather than by a single fixed textbook rule.
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Alkyl C-H | 6 | 6 | 1.0 |
| Hydroxyl (O-H) | 4 | 4 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| C n single bond | 2 | 2 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Nitrile | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| S eq o | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 0.7 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| Chitosan | 1336, 1650, 1655 | Alkyl C-H, Amide, Hydroxyl (O-H) | 1 |
| starch | 1336, 1650, 1540 | Hydroxyl (O-H), Alkyl C-H, Amide | 1 |
| Nanocellulose | 1336, 1540, 1646 | Alkyl C-H, Amide, Hydroxyl (O-H) | 1 |
| CMC | 1336, 1423, 1196 | Hydroxyl (O-H), Alkyl C-H, Amide | 1 |
| rGO | 1336, 2358, 2930 | Hydroxyl (O-H), Alkyl C-H, Amide | 1 |
| Fe3O4 | 1336, 2358, 1673 | Hydroxyl (O-H), Alkyl C-H, Amide | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
Spectrum logic
This band becomes meaningful only when read with its neighboring peaks. In practice, analysts first look at the assignments above, then check whether the same sample also shows other peaks expected for the same structural motif. A lone band near 1336 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
Literature behind these assignments
-
Alkyl C-H confidence 1.0
“The HWS spectrums displayed CH twisting at 2 1336cm-1 cm-1 and CWS samples spectrum were shifted to higher ones at 1357-1367 indicating cm-1 RIPT C-H symmetric bending of CH in CWS spectrums.”
Butt 等 - 2019 - Rice starch citrates and lactates A comparative s DOI: 10.1016/j.ijbiomac.2019.01.019 -
confidence 1.0
“1g Journal cm-1 cm-1that sharp peaks appeared at1600.89 and 1335.87 corresponds to G-band and D-band respectively for 5mM Fe 3O 4/rGO nanocomposite [33].”
Devi 等 - 2020 - Investigation of chemical bonding and supercapacit DOI: 10.1016/j.diamond.2020.107756 -
Amide confidence 1.0
“An explanation of these changes when AZA reacts with ST-namely (i) the downshift of the explanation of these changes when AZA reacts with ST-namely (i) the downshift of the IR band of AZA from 1336 cm-1 to 1331 cm-1, the band attributed to”
Photodegradation of Azathioprine in the Presence of Sodium Thiosulfate DOI: 10.3390/ijms23073975 -
Alkyl C-H confidence 1.0
“2 1376 C-H deformation vibrational Cellulose 1336 O-H in-plain deformation”
Micro-FTIR combined with curve fitting method to study cellulose crystallinity of developing cotton fibers DOI: 10.1007/s00216-020-03094-6 -
S eq o confidence 1.0
“In the spectra of complexes (II) and (III), the unbound sulfonyl group was described by two νas(SO2) bands, which were located at 1356 cm-1 and 1336 cm-1 for (II), and at 1347 cm-1 and 1334 cm-1 for (III).”
Study of Lithium-Extraction Systems Based on Benzo-15-Crown-5 Ether and Alkylimidazolium-BasedIonic Liquid DOI: 10.3390/molecules28030935 -
Amide confidence 1.0
“The literature states that the imine group's (CH=N) characteristic absorption cm-1) band (1660-1630 cannot be observed clearly, probably because it overlaps with the spectrum was shifted at 1336 cm-1 and split into many other lower intensit”
Hydrogel Films Based on Chitosan and Oxidized Carboxymethylcellulose Optimized for the Controlled Release of Curcumin with Applications in Treating Dermatological Conditions DOI: 10.3390/molecules26082185 -
Alkyl C-H confidence 1.0
“A significant increase of the absorption band transmittance at 1426 cm-1 assigned to the C-H cm-1 A significant increase of the absorption band transmittance at 1426 assigned to the C-H bending [64] and of the absorption band at 1371 cm-1 a”
Bacterial Nanocellulose from Side-Streams of Kombucha Beverages Production: Preparation and Physical-Chemical Properties DOI: 10.3390/polym9080374 -
Hydroxyl (O-H) confidence 1.0
“The wide band at 3441 represents the cm-1 cm-1 cm-1, around 1336 O-H stretching vibration.”
Hamisu 和 Celik - 2017 - Poly(AN-co-PEGMA)hBNNaClO4 composite electrolyte DOI: 10.1515/epoly-2017-0022
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